Long-wavelength and low-fluence UV-B light is an informational signal known to induce photomorphogenic development in plants. Using the model plant Arabidopsis thaliana, a variety of factors involved in UV-B-specific signaling have been experimentally characterized over the past decade, including the UV-B light receptor UV resistance locus 8; the positive regulators constitutive photomorphogene...

Ellagic acid, a polyphenol compound present in berries and pomegranate, has received attention as an agent that may have potential bioactivities preventing chronic diseases. This study examined photoprotective effects of ellagic acid on collagen breakdown and inflammatory responses in UV (ultraviolet)-B irradiated human skin cells and hairless mice. Ellagic acid attenuated the UV-B-induced toxi...

Ultraviolet (UV) radiation is an important constituent of sunlight that determines plant morphology and growth. It induces photomorphogenic responses but also causes damage to DNA. Arabidopsis mutants of the endonucleases that function in nucleotide excision repair, xpf-3 and uvr1-1, showed hypersensitivity to UV-B (280-320nm) in terms of inhibition of hypocotyl growth. SOG1 is a transcription ...

BACKGROUND Most studies of the transcriptional response to UV radiation in living cells have used UV doses that are much higher than those encountered in the natural environment, and most focus on short-wave UV (UV-C) at 254 nm, a wavelength that never reaches the Earth's surface. We have studied the transcriptional response of the sunlight-tolerant model archaeon, Halobacterium sp. NRC-1, to l...

Human blood dendritic cells require UV-B radiation (290 to 320 nm) in excess of 1,000 J/m2 to inhibit their stimulation of primary T-cell responses to alloantigen by 60% to 70% or more. The effect is twofold to threefold greater in the allogeneic mixed leukocyte reaction (MLR) than in polyclonal mitogenesis using comparable numbers of dendritic cells and doses of UV-B radiation. UV-B radiation ...

UV-B radiation induced alterations in the contents of photosynthetic pigments, antioxidants (phenolics and ascorbic acid) and chlorophyll fluorescence in two tropical variants of Trichosanthes cucumerina L. – Cucurbitaceae. The Green (Variant A) and Light Green (Variant B) variants of T. cucumerina, which had earlier been shown to differ in their total phenolics contents, were used for the stud...

Colorless phenylpropanoid derivatives are known to protect plants from ultraviolet (UV) radiation, but their photoregulation and physiological roles under field conditions have not been investigated in detail. Here we describe a fast method to estimate the degree of UV penetration into photosynthetic tissue, which is based on chlorophyll fluorescence imaging. In Arabidopsis this technique clear...